Copy site to server

i've been making a small site in my pc using Visual Web Developer 2005 express edition and everything works. when i upload the project to a server it starts to give some weird errors. some i've already solved, others...
the one annoying me rigth now it's this one: Compiler Error Message: BC30451: Name 'func' is not declared. , where func it's a public class in a (class.vb file the file is in the App_Code folder).
does anyone knows why does it works in a local machine but not in a remote web host?

ok, i compiled my class.vb into a dll and then i add it as a reference.
now i use class1.func.bd("...") to call the functions, and it works great on my pc. on the server where i deployed the site, it doesn't work...it gives the same error: Compiler Error Message: BC30451: Name 'class1' is not declared. please help me............

the problem was the location of the bin folder in the server. i was uploading the entire site to a folder in the httpdocs, like this: /httpdocs/test/... , but it must be like this:
the site -> /httpdocs/test/... the bin folder -> /httpdocs/bin the bin folder must be always in the httpdocs folder and the site can be anywhere in httpdocs folder...